Stop motion for roving frames



Nov. 10, 1953 s; J. ADAMS STOP MOTION FOR ROVING FRAMES 2 Sheets-Sheet 1 Filed May 25, 1949 s/m sa/vdAoAMs l9 TTdRlVEY Nov. 10, 1953 s; J. ADAMS 2,658,326

STOP MOTION FOR ROVING FRAMES Filed May 25. 1949 2 Sheets-Sheet 2 HTI'ORNEY Patented Nov. 10, 1953 UNITED S TATES PATENT 0F Fl-CEE STOP MOTION FOR ROV-ING FRAMES Simpson J. (Adams, Abbeville, is. 0.

Application May '25, 1949, Serial No. 9'5,231

.8 "Claims.

I his invention relates :to textile machinery and in particular to arrangements for automatically stopping the machine when a strand :of textile material beingoperated-on by the machine breaks "or acquires :an excessive amount of slack. The invention is especially :adapted for "use on :roving machines and machines of a similar nature :in which a strand of textile material is twisted :and "is wound upon a bobbin by :a builder imotion.

The invention is also :concerned with an :improved formof dropwire .for use in aEStODmOtlOIl, and in arrangements for mounting :the drop wire.

In the operation of stop motions on textile machines in which a strand of .fiber is being wound upon a bokibin by -huilderi-moti'on, such for example asshown in my prior Patent;2,'129.,639.,if the machinershouldzbestopped when the traversing motion of the bobbin :firame :is either at the "top or the bottom .of :the stroke, "there :is con-- siderable likelihood that the roving strand will over one of the end 'cones-zof'thezroving wound on the ibobbin. 'ZIhis would result in slack sbeing introduced into the strand involved and would :prevent the machine utrom dieing restarted :even though the iGOIIdltiGIl which "caused the machine to stop originally was :remedied.

IObjBCtidf the invention is to devise anarrangement for preventing operation Kdf the :stop tmo'tion (during the :periods when the'builder smotion reverses :the =-direction of movement of :the

:to :devise an electrically controlled stop motion in which the :stop circuit is :controlled automatiaca'lly :by the buil'derimotion of the textile :machine to :open the (circuit during "each :reversal :of the bobbin :frame traversing mechanism.

(A iurther object of the invention is 'to devise animproved arrangement :for mounting the :drop wires .of the stop :motion on the textile machine.

:Still another object is "to :devise :an improved form .of drop wire :having a circular -:eye for .receiving :thestrand and operating to heat :down the long fibers at a .pointwhere the strand is *being twisted.

Still another object is to devise an improved form of drop wire of adjustable length and hav ing a "replaceable eye.

A further object of the invention :is to :devise an improved drop wire arrangement in which the drop wires engage the textile strands in a position normally inclined to the vertical and operateto close the stop circuit when-move'd'to a substantially vertical position.

Another feature of the invention "is the pro- 2 vision of a trip bar for simultaneously raising the inclineddrop wires out :of :contact with :the strands when the machine is to be dofied.

My invention is illustratediin the accompanying :drawingin'which Figure 1 is :a diagrammatic view showing :a fragmentary part of a roving machine in *liiront elevation;

Figure '2 is a sectional view 10f Figure i1 taken along -:the iline12-l2 and showing two :flyers rand associated'bdbbins;

*Eigure 3is :a plan ViGW-Ldfithe trim or :edge strip showing .llhB'IlOtCI-IES formedtthere'in for receiving the drop wires;

Figure 4 :is an (enlarged sectional -view "taken in 'a vertical plane through one of the :drop wires and its mounting: arrangement;

FigureT5 is :aaside zelevationail new of armadifiBd?SWitCh arrangement controlled hy t'he bnilder :motion;

Figure .6 is :a diagrammatic "view similar to Figure 1 of afragmentaryzpart of a roving :machine in front :elevation .and showing :a {different nrrangemen'tfior mounting the {drop wires;

Figure '7 is a :view similar to 'iligure '6 showing :still another arrangement zfor amounting the drop wires, and also showing a trip :bar for simultaneously raising all ref the drop wires; and

Figure 815.533 sectional view of Figure '7 taken along {the li'ne18i8.

Referring to it-he :drawing, gpower driven draft "rolls of the moving :machine are indicated :at 4 :and the cooperating ltQI) :rolls, which-are usually covered with cork or leather, are shown :at The draft :rolls :are :journaled upon suitable brackets 31mounted upon .themachi-ne (frame .4. *Asshown in Figure z-lpth'e draftmolls 2| ;andi2-.comprise a series of .longitudinal sections engaging each other, zandza strand or sliver is fed :to :the back pair of :rolls mf (each section by ,means -;of a guiding trumpet 5. The sliver :is passed successively between the second and third :pair of draft mus and :extends i150 rotating flyers :arranged in front of the roving machine. .In Eigure :2, $11 rovling cor strand 6:: extends to the river I111 in the backrowof dlyers, whilefthe trovingifib extends to :a fiver located .in xthei-"iront row of :flyers. Alternate rovings, therefore, arezassooia'ted with "the :flyers in alternate rows. The rtwo :fiyers 111- 'and Th wind :the moving ':on bobbins To and 21d respectively. These bobbins are :carried .=by :a vertically movable carriage 8, and the spindles We and '12 of flyers 1a. and lb extend downwardly through the carriage 8 to suitable driving means not shown. A "conventional builder motion is employed to reciprocate the carriage 8 vertically through a constantly decreasing throw as the yarn builds up on the bobbins, thus forming the cone-shaped ends at the top and the bottom of each bobbin as shown in Figure 2.

Each roving is provided with a pivotally mounted drop wire having a circular eye through which the roving passes. In the preferred arrangement illustrated in Figures 1 to 4, each drop wire is adjustable in length and is formed of two telescoping parts, that is, a sleeve 9, pivotally supported at its lower end, forms the lower part of the drop wire, while a length of wire l0 having a round eye Illa at its upper end, and having its lower end extending into and being frictionally supported by the sleeve 3, constitutes the upper section of the drop wire. The sleeve 9 is preferably formed of thin metal, and the necessary frictional contact between the sleeve and the wire l0 may be secured by forming a number of dents So at spaced points along the sleeve 9.

The arrangement for pivotally supporting the lower end of the drop wire is illustrated in detail in Figure 4. As shown, the lower end of the sleeve 8 is mounted in a radial socket formed in r a bearing sleeve H which is journaled upon a screw l2 which is centrally mounted within a hole formed in a vertical wall 4a of the machine frame by means of a pair of flanged bushings I3 formed of insulating material and held in position by a clamping nut l4 threaded on the screw l2. A pair of lock nuts l5 are threaded on the outer end of the screw l2 and serve as a stop to hold the sleeve II on the screw 2. The drop wires are pivotally supported on the vertical wall 4a below the usual edge or trim plate l6, and each drop wire extends vertically upward through a notch |6a formed in the trim plate. By the arrangement shown, the drop wires are supported on the wall 4a in insulated relation, and all of the drop wires are connected together by a conductor I1 which may be clamped between the lock nuts IS. The arrangement is such that so long as all of the drop wires remain in a vertical position, the conductor I1 is insulated from the frame of the machine, but if any drop wire tilts in either direction beyond a certain amount, the sleeve 8 comes into contact with one of the edges of the notch |8a and grounds the conductor IT to the machine frame. in the energizing circuit of a stop relay or other device which operates to stop the machine when contact is made by any drop wire with the trim plate l6.

For the purpose of preventing operation of the stopping circuit during the reversal of the bobbin carriage, the stop circuit is completed through a special electric controller or switch which is controlled by the builder motion and operates automatically to open the stopping circuit just before the bobbin carriage reverses its direction of motion, and the controller maintains the stopping circuit open until the direction of motion of the carriage has been reversed. One suitable form of controller is illustrated in Figure 2 in which the essential parts of the builder motion are illustrated diagrammatically. In this arrangement, the builder motion includes a bracket I8 which is mounted upon and movable with the bobbin carriage 8. A shaft I9 is journaled in the parallel arms la and lb of the bracket |8 and supports the upper and lower jaws 2|] and 2| of the builder motion, one of these jaws being connected to the shaft I!) by a right-hand thread, and the other by a left-hand thread, so that ro- The conductor I1 is connected tation of the shaft l8 in one direction will cause the jaws to approach each other, and rotation in the opposite direction will cause the jaws to separate. As will be understood by those skilled in the art, the jaws 20 and 2| serve to release the tumbler shaft (not shown) when the dog on the tumbler shaft rides on of the jaws on the upward and downward strokes of movement of the bobbin carriage 8. Each step of rotation of the tumbler shaft effects reversal of movement of the carriage 8 and also effects a limited rotation of the shaft 19 to move the jaws 28 and 2| closer together, and thereby effects earlier reversal of the movement of the bobbin carriage 8 on each traverse movement of the carriage.

The special controller shown in Figure 2 involves a contact plate 22 mounted upon and movable with jaw 20 and a second contact plate 23 arranged parallel with contact plate 22 and being mounted upon and movable with jaw 2|. A spring-like contact finger 24 is supported upon a fixed arm 25 and extends transversely across contact plates 22 and 23. The arm 25 is either formed of insulating material, or else the contact finger 24 is mounted upon the arm by an insulating connection. The arrangement is such that as the carriage 8 moves up and down, the contact finger 24 will maintain contact with either plate 22 or plate 23 until these plates move out from under the finger 24 in either direction of movement of the carriage 8. The plates 22 and 23 may have electrical contact with the jaws 20 and 2|, or they may be supported upon these jaws in insulated relation. In the arrangement shown in Figure 2, the plates 22 and 23 are electrically connected to the jaws 28 and 2|. The contact plates 22 and 23 are of such length that they overlap each other at all times, and the outer ends of these plates are positioned so that the spring contact arm 24 will ride oil of the outer ends of the two plates just prior to disengagement of the dog of the builder motion with one of the jaws 2|) or 2|, and contact remains broken between the arm 24 and one of the plates 22 or 23 until after the carriage 8 has been reversed in direction of movement.

The stopping circuit shown in Figure 2 is connected between the conductor joining the drop wires and the contact finger 24 of the builder motion controller. The circuit includes a manually operable cut-off switch 28, a source of operating current represented by the step-down transformer 21 which is connected to a suitable source of alternating current, and a suitable stopping relay or magnet 28. The magnet 28 controls any known form of device which operates to stop the machine when the magnet is energized.

Operation of the arrangement shown in Figures 1 to 4 is as follows: Under normal operating conditions, the switch 26 is closed, and so long as all of the drop wires remain in vertical position. the stop circuit is open-circuited and the machine continues to operate without interruption. In case one or more roving strands should break or become unduly slack, one of the drop wires will tilt about its pivotal support and will make contact with the edge of one of the slots l6a, thereby closing the stop circuit through the frame of the machine and energizin the stop magnet 28 to stop the machine. The return path for the stop circuit is completed through the frame of the machine and through the builder motion to the contact plates 22 and 23, and from these plates through the finger 24, and through connection 28a to the magnet 28.

anemone If one of the drop wires should make contact with the edge plate l6 at a timewwhen the oontact finger 24 has broken contact with rtheaplates '22 and the :machine "will noritinue operation until the direction :of motion of the ithobbin narfniage ".8 has ibeen :reizersed, andrthe .s'top :circuit wvill not he energized runtil the icfilitalit :finger L24 reestablishes contact with [one of the ,.plates .22 0123.

.InfFigure 52E havezshowma side eleuationalwliew =nf 5a modified :form of abuilder motion icontroller which .may he used instead of the arrangement shown :Eigure 2. In .lthlS the ;a1m.:25 :suppnrtspn :its upper send a zbracket :29 which :has n rearwardly iexten'ding arm 32911 rpmauiding a "pivotal suppoztiforsanleuer 3%.. Arminitact'zroller 13-1 'is carried at the ilower (end of the lever 39 :and is :positioned to :bnidge dzhe icontaet plates 2:2 and 2 4A sspring dznmmeeted :between the bracket 29 :and the upper .end :of the arm I30 urges the contact roller I31! into engagement with *the :plates $22 and 2:3, :and .an adjustable stop :screw .33 .is JIIlOllIItEd on .the bracket -29 and ar- :ranged to limit "the amount iof movement :of the ilever 30 when .themoller ilil :rides of thesouter :ends of the :plates 22 :or 23. If the lever 31] and the roller :31 .are .formed of aconductingrmateiiial, these elements will serve the same function as .contact finger 24 .in Figure :2 by providin fthe (connection 18a .:from the ileverrfifl to Lthemagnet L28. Instead :of having rthe Jeverfiloperdteas an electricaliswitch element, this Elener :mayzserve to operate :a :separate switch 34, such :as a :miero- :switch, mounted upon "the arm 12.5 :in a :position so;that1the;lever ;-3fl;engages tthe-ioperating plunger -01 the sSWitCh :and normally :holds ithe .switch in open position when the roller .3 is.=ri'ding upon either plate 2-2 or ibu't rthe swlitch moves to closed 'positionwhenthe :roller :31 illd'BS .ofi f the end :of either p'late. .Inithis KCBISG, one terminal .of the switch .34 would ".be :grounded ito the frame of "the machine and the rather terminal would :be connected to the --magnet 28 through :connec'tion 28a.

3111 Figure 6 .I .have illustrated .a Fsomewhat ditiferent arrangement for mounting ithe drop Wires of the :stop motion. Instead ofssupportin-g the drop "wires below 'the strands or :roving lE'ig- :ure 1, the :drop wires are apivotally isupported above the roving zantl are nonnailly arranged an inclined tposition. :Eor this purpose, 2a fiber 135 formed of insulating :matenial iis zsupplmted above the moving :and marallel with ithe draft rolls by suitable ibrackets 1-3.5 secured to ithe iframe -4 and 'spaced .along "the "bar .35. drop wires employed in Figure 16 :are :of ,the same :construc- '-tion :as shown in Figures :1 to 4,, lbllt ithe pivoted ends are supported on the :bar 115 linlmrizontally offset relation with respect :to the mentioal zplama 0f the roving passing through bhBlLIQJlIId reve inf .eachadrop wire. As inFigure the pivotsdadrnp wires are connected together by rconduotor :lzl. .Each drop wire is provided withn-nontactlpin 31 supported upon the bar .3-.5 directly 'below :the

pivotal axis of the drop wire and extending :in

front -.of the bar .35 into the ;plane of movement of the .drop wire. All .of the pins 23:! are :connected together by 13, aconductor =l'la which may be grounded to the frame of the :machine if 'desired. It will be understoodthatzthecconductors l1 and 17a are-connectediin the-stopping mincnit so that the-circuitwill beenerg-ized when these two conductors are connected :together by Len-- :gagement :of one of $116 stop wires with :one :of the pins 31.

in the :normal operation .of the =-arransement ashowntin Figure .6, the moving from the draft :rolls .pass through the eyes of the drop wires :and maintain the'dropwires in an inclined position as .shown :in :the :drawing 150 that the drop wires do not engagethegpins 31. If a .roving should tbreak 'or sshould become (unduly slack, the drop wire will sswing downwardly towardsthe vertical position 'and'will come in contact with one'of the ins :31 :and thereby complete the stopacircuit'and iefiect stopping of themachine.

InFignres 7 :and '8 .Ihave illustrated still another variation in the arrangement *for mounting 'sthe drop wires. In this arrangement, the drop wires are pivotally supported above the :roving upon .an insulatin bar 35in generally thersame manner as in .Figure 6. The bar 35 may be mounted vupomfixed rbrackets as in Figure :61, but inzthis arrangement .I prefer to mount the-har on the forward edge of the draftroll .coveradB "which is pivotally mounted at its rear edgefas represented at 39. .By mounting the drop' wires :in this manner, all of the drop wires arezra'ised and moved out of the way when the roll cover 3.8 is raised for inspection of the rolls or .for'the cleaning of the roll clearers carried 'by'the cover.

The drop wires in Figures 37 and 5 also wary somewhat from the arrangement shown in .Fig- "ure '6 in that the wires are not adjustable length but the wire ilio :is secured .direictly 3110 :the bearing :sleeve H. Also, -inst'eax l .of uprovi'ded with round eye .at the .ends of the drop wires, thewires merely rest :upon the roving :in .an inclined position'rassshown .in iEigure .7., and in order to prevent damage to the roperatorfis hand by the sharp ends of the drop wires, the ends of the wires may be turned ibackias zshown at [01). .Each dropwire is provided with anon- 'tact :pin 3 as in Figure 5, and the operation of the arrangement shown in Figures l7.-and .8 will be readily understood from the -above descrip- .tiono'f operationo'f Figurefi.

In the arrangement :shown in Figures 17 and 8, operation of the machine will be facilitated, especially when the moving machine is to :.be defied, if all of :the :drop wirescan ebesraised out of contact with the strands simultaneously. .Eor :this purpose, [have .providedga rod l0 arranged below !the xlower Ledge iof Ihar 35 and :extending throughout the length :of thisbar. Therod 4.0 is preferably =of square sectionzan'd is "mounted :fior sliding zmovementrailongithe bar by means :of suitable-straps 'll 'securedto :the barf35. One DI Ebo'th ends of the ilOd are "bent to provide ;a .ihandle .pontion Ada for use in sliding thexrod. A plurality :of pins 4.2 are supported upon the rod :40 ralongiits length :and .extend-fonwardly-of the .I'Qd tthrouglh the ."plane of movement of the (drop wires 10., there being one :pin -42 :for each drop wire. .During normal operation of the machine, the rod 4.0 :is positioned asshown in Figure '7 that the pins d2 :are positionedbelow the drop wires ill but :do notsengage :the drop wires. By shifting the rod-d0 to theleft, the pins 42 simultaneously engage all of the drop wiresrandcause them its rotate clockwise through a limited an- :gular :movement :and thereby :raise :the wires ifrom contact with the strands. As soon as the operator has finished dofling the machine, he the :rod 40 to the :right, thereby :allowing :the :drcp \WlI'CS to resume their normalwoperating position in contact with the roving.

I-he inclined \drop .Wire arrangements shown :in Figures 15 and '7 involve the use of onlyone cooperating acontaot for each drop Wire, and

mounting the drop wires in an inclined position, the amount of weight applied to the roving is considerably reduced. For example, the weight applied to the roving is considerably less than one-half the weight of the drop wire, exclusive of the weight of the bearing sleeve II.

By forming the drop wires to be adjustable in length, as shown in Figure 4, the same drop wire may be used for both the front and back rows of flyers, it being necessary only to adjust the length of the wire to place the eye in the proper position for either row. Also, the adjustability of the drop wire makes it possible readily to adapt the drop wire to different mounting arrangements on machines of different manufacture. A further advantage of this arrangement is that in case the eye of the outer end of the drop wire should become damaged, it can be quickly replaced by pulling out the damaged part and inserting a new one. This change can be made by the operator of the machine and does not require the services of an electrician.

The use of a drop wire having a round eye through which the roving passes has a distinct advantage in connection with the working of roving having long fibers. For example, heretofore it has not been possible to successfully work roving having more than 50% acetate fibers, because the long acetate fibers in the roving caused an uneven yarn in the spinning operation, and other difficulties arose. I have discovered that it is possible to work 100% acetate roving if the roving is passed through a round eye as it passes from the draft rolls to the flyers, the eyelets being positioned so that the roving passes through the eyelet in a straight line. The explanation for the successful operation i that as the roving passes through the eyelet, it is being twisted by the fiyer with the result that in addition to having longitudinal end twisting motion, the roving also rotates around the inside of the eyelet. For example, as shown in Figure 5, the eyelet is of relatively large diameter with respect to the diameter of the roving 6, and as the roving passes through the eyelet, it also revolves around the inside of the eyelet, for example, in the direction shown by the arrow. The rotation of the roving around the inside of the eyelet while the roving is being simultaneously twisted causes the long fibers to be knocked down and twisted into the roving, thereby re sulting in a rounder roving which in turn spins a smoother yarn than yarns produced without the knocking down operation. It will be obvious that the eyelet need not be formed as a part of the drop wire in order to obtain this advantage of my invention, but the same advantage may be obtained by an independent eyelet supported in the proper position for securing rotary motion of the roving around the inside of the eyelet. For this result, it is necessary that the eyelet should be positioned at a point Where the roving is being twisted and that the roving should pass through the eyelet in substantially a straight line.

The inside diameter of the eyelet i not especially critical, but it might vary somewhat with the weight of the roving. I have found that successful results may be obtained by using eyelets having inside diameters varying from T g inch for the lighter roving to inch for the heavier roving. The rate of rotation of the roving around the inside of the eyelet will depend upon the amount of twist being applied to the roving and, on the average, the roving will rotate about one revolution per inch of linear travel of the roving.

I claim:

1. In a textile machine having a builder motion for building a textile strand upon a bobbin in successive layers of progressively decreasing length, said builder motion including a pair of traversing jaws which move progressively towards each other, the combination of a slack detector arranged to detect slack in the strand supplied to the bobbin, an electrically operated stop device for said machine having an energizing circuit, a pair of normally open contacts embodied in said slack detector for energizing said circuit when said yarn acquires a predetermined amount of slack, a switch device connected in series with said circuit and comprising a pair of parallel overlapping plates of conducting material mounted upon and movable with said jaws, and including a stationary contact member cooperating with said overlapping plates to control said energizing circuit, said switch device being arranged to maintain said circuit closed so lon as said stationary member engages one of said overlapping plates and to open said circuit when said stationary member rides off of said plates at either end of the traversing movement of said aws.

2. In a textile machine in which a textile strand is supplied from draft rolls to a fiyer and in which a builder motion builds the strand upon a bobbin in successive layers of progressively decreasing length, the combination of a slack detector arranged to detect slack in the strand supplied to the bobbin and including a round eyelet surrounding said strand and having an internal diameter substantially larger than the diameter of said strand and being positioned so that said strand passes through said eyelet in substantially a straight line, an electrically operated stop device for said machine having an energizing circuit, a pair of normally open contacts embodied in said slack detector for energizing said circuit when said yarn acquires a predetermined amount of slack, said slack detector comprising a drop wire pivotally mounted at its lower end upon a fixed support and carrying said eyelet at the upper end thereof, said machine being provided with a trim plate having a notch formed in the edge thereof and said drop wire being pivotally supported below said trim plate and normally extending vertically through said notch, the opposite edge portions of said notch constituting stationary contacts for completing said energizing circuit when said drop wire comes into engagement therewith, a switch device connected in series with said circuit, and means controlled by the operation of said builder motion for maintaining said switch device closed during the traversing movement of said builder motion and for opening said switch device during the reversin periods of said builder motion.

3. In a textile machine in which a plurality of textile strands are supplied from draft rolls to a row of flyers arranged parallel with said rolls, the combination of a bar mounted above said strands between said rolls and said fiyers and arranged parallel with said row of flyers, a plurality of drop wires, one for each strand, means attaching one end of each drop wire to said bar for pivotal movement about a horizontal axis arranged at right-angles to said bar, the points of support of said drop wires on said bar being horizontally ofiset along the bar with respect to the associated strand, and said drop wires being arranged to engage said strands and normally being supported by said strands in positions inclined to the vertical, and a plurality of electrically insulated contacts carried by said bar, one for each drop wire, and arranged in the plane of movement of said drop wires below the pivotal points thereof whereby when a strand acquires a predetermined amount of slack, the associated drop wire will move into engagement with the associated contact.

4. A textile machine according to claim 3 wherein said drop wires are provided with round eyes at the free ends thereof and arranged to surround said strands in a location where said strands are being twisted and pass through said eyes in substantially a straight line.

5. A textile machine according to claim 3 wherein said machine includes a pivotally mounted cover for said rolls, and said supporting bar for said drop wires is carried by said cover, whereby said bar and the attached drop wires may be moved out of engagement with said strands by raising said cover.

6. A textile machine according to claim 3 and including a rod mounted for sliding movement adjacent the lower edge of said bar, and a plurality of abutments carried by said rod and extending into the planes of movement of said drop wires and being operable, upon longitudinal shifting of said rod, to raise said drop wires from engagement with said strands.

7. A drop wire assembly for a textile machine comprising an elongated bar, a plurality of drop wires pivotally supported at one end at spaced points along said bar, an individual insulated contact element mounted upon said bar below the pivotal point of each drop wire and arranged to be engaged by the associated drop wire, a rod mounted for sliding movement with respect to said bar below said contact elements, and a plurality of abutments carried by said rod and arranged within the planes of movement of said drop wires and being operable upon shift- 10 ing of said rod to move said drop wires out of engagement with said contacts.

8. In a textile machine having a builder motion for building a textile strand upon a bobbin in successive layers of progressively decreasing length, said machine including a vertically reciprocating frame supporting said bobbin, and said builder motion including a pair of overlapping jaws mounted to reciprocate with said frame and including means for progressively moving said jaws into increasing overlapping relation, whereby the distance of separation between the outer ends of said jaws progressively decreases, the combination of a slack detector arranged to detect slack in the strand supplied to the bobbin, an electrically operated stop device for said machine having an energizing circuit, a pair of normally open contacts embodied in said slack detector for energizing said circuit when said yarn acquires a predetermined amount of slack, a normally closed switch device connected in series with said circuit and located adjacent said traversing jaws at a point mid-Way of the vertical traversing path of said jaws, and means carried by said jaws for opening the contacts of said switch device when the outer end of either jaw moves past said switch device.

SIMPSON J. ADAMS.

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